Cabletron Systems CSX1000 - Manual (Page 635)

Workgroup Remote Access Switch 635
C AUSE C ODES T ABLE
UNKNOWN Indicates that an event occurrent but that the network does not
provide causes for the actions that it takes, therefore the precise
nature of the event cannot be ascertained. This may, or may not,
indicate the occurrence of an error.
Dec Value Hex Value Q.931 Cause